--On 12 June 2003 15:42 +0100 Ian Shaw <address@hidden> wrote:
As I understand it, on a 1-ply evaluation of a position, the net is fed
all 21 possible return rolls for the opponent, and the equities of the
best moves are averaged. The equity for the original player is then one
minus this average. If the net tends to overvalue the equity of the side
on roll, then the 1-ply equity will tend to be lower than the 0-ply
equity. We would then expect this trend to continue for even and odd
plies.
Yes, this is a true implication. I don't know whether the 0-ply evals
ARE too high on average. I would suspect something like that would have
caught Joseph's eye
Furthermore, I just realised one possible cause for difference between
0-ply and 1-ply:
If 0-ply is unbiased but imprecise (as in having average error 0) then
the value of the best move will be overrated.
Example
Move True Equity 0-ply equity
A 0.4 0.35
B 0.4 0.45
C 0.5 0.45
D 0.5 0.55 (*BEST MOVE*)
Note that the average error is 0, but the best move is off by 0.05.